Nicolas Ghesquière is leaving Balenciaga after 15 years as the house's creative director. The brief announcement in Women's Wear Daily says the designer and the company made a "joint decision to end their working relationship" effective the end of this month. No word on what prompted Ghesquière's departure, or whether it is in fact voluntary; the designer has presided over Balenciaga during a period of tremendous growth (particularly in its accessories category with trend-setting best-sellers like the motorcycle handbag) and relationships with top celebrities including KStew, all while maintaining cred with the fickle high-fashion elite. To call this news unexpected is an understatement. [WWD]

Kate Upton looks unsurprisingly sexy posing on the roof of a Manhattan skyscraper in black latex fetish gear in this behind-the-scenes video for Vogue Italia. [YouTube]

Tim Walker shot Anna Piaggi, wearing her own clothes and accessories, for W magazine just one month before the legendary fashion editor's death this August. This is the resulting series of portraits. [W]

Jenny Packham is doing a holiday collection of accessories for J.C. Penney. Vivienne Tam and Lulu Guinness also designed capsule collections for the retailer. [Stylebistro]

Fashion historian Valerie Steele, the curator and director of the Museum at FIT, gave a wide-ranging interview to Fashionista. She says of street style photography:

"It's a very interesting phenomenon and I think it's good for fashion, that people are dressing up to be seen and to be photographed. I think that in order for fashion to flourish, you really need to have a culture where people are performers and also sort of knowledgable observers and connoisseurs."

New York magazine hangs out with Solange Knowles in Red Hook, Brooklyn, near her recording studio:

"It's got some pajama vibes, but it works," she says of her outfit. Her Technicolor coat is on permanent loan from Alberta Ferretti, for whom she recently did a runway show in Milan ("They forgot to ask for it back"), and she's paired it with neon-orange socks, open-toed heels, and an Afro wig. Most of the men loitering outside bodegas and 99-cent stores don't recognize her as a singer-or as Beyoncé's younger sister — but they do recognize that she looks good. "Beautiful. I like your style," says one, mouthing a kiss.

Later, a strange man on the street offers her chicken jambalaya out of a styrofoam container. "I just ate," says Knowles. "Otherwise, I would totally dig into that." [Vulture]

"Things like blogs and the Internet are so important now." This is a thing that the Sartorialist, Scott Schuman, said in an interview. He also held forth on Bill Cunningham, the legendary photographer of the New York Times's On The Street column:

"You know, I hate to say it, I'm sure everyone thinks he's a lovable guy, and I'm sure he is. We've never had a conversation. The only conversation we've ever had is when I'm trying to shoot someone and he says, ‘Hey, get out.'

"The only influence he's had on me is that I want to be doing that when I'm 80. That's the only thing. I want to be on the bike, I want to be doing that at 80.

"His photographs, I think they're nice, they're just a totally different style from me. I don't think they're bad, really just a different style. He's really reportage, shoot, snap, he's just going, going, going. His only influence has been in the quality of the effort he puts in and the joy — you can literally really see it on his face, the joy that he still has for fashion."

The Mall of America just turned 20. Its impact on the Minnesota economy through sales and tourism is around $2 billion annually. [WWD]

The producers of the Victoria's Secret fashion show helped the National Guard power its base at the Lexington Avenue Armory during the blackout after Hurricane Sandy. The company, which tapes its fashion show inside the armory every year, let the National Guard use the generators and communication system it had installed in anticipation of the event. [Wired]

Speaking of Victoria's Secret, Jourdan Dunn and Cara Delevingne are both set to make their debuts in this year's show. [Telegraph]

Leonardo DiCaprio and Erin Heatherton reportedly broke up last week. Don't worry, the actor is already "partying with a gaggle of models" at Cipriani. Stick with what works! [P6]

Tiffany & Co. is planning to open a store on the Champs Elysées in Paris. [WWD]

Amazon.com is continuing to expand its fashion retail business, which category it finds profitable and fast-growing. Amazon is leasing a 40,000-square-foot space in New York to photograph clothing and accessories for the main site as well as Shopbop and MyHabit, which the company owns. The studio will be in Williamsburg, and will employ a small staff in addition to a roster of freelance photographers, stylists, models, makeup artists, and hair stylists that will likely number in the hundreds. [WWD]

Gaspard Ulliel — the totally hot dude from A Very Long Engagement, remember him? — has been cast as Yves Saint Laurent in an upcoming French biopic. Bertrand Bonello is attached to direct. Meanwhile, another Saint Laurent biopic, to be directed by Jalil Lespert, has won authorization from the designer's widower, Pierre Bergé. [Vogue UK]

Karl Lagerfeld is adding a licensed line of watches, produced by Fossil, to his namesake brand. [WWD]

Lawrence Lenihan, a professor at NYU's Stern School of Business, has harsh words for most of the fashion start-ups he sees cluttering the Internet with "virtual closets" and flash sales and crowd-sourced this and that:

The biggest flaw I see is that these "Internet entrepreneurs" fail to understand how the Internet will fundamentally transform the fashion industry, not just provide another access point to buy something.

In my opinion, the biggest change will be a dramatic shift in the relationships amongst brands, retailers and customers. Going forward, every brand must figure out how to connect directly with its customers and they must structure their business around the relationships they want to have with their customer rather than let their distribution channels define them. The economics are too great not to do so.

Elizabeth Arden's efforts to reposition the brand have hurt its profitability in recent months, but not its sales. In the quarter just ended, net income fell year-on-year by 76.3% to $2.2 million. Sales rose by 13.5%. [WWD]